The present invention relates generally to drive tools for installing fasteners, and relates more specifically to a drive tool which does not require any upper-body force from an operator to install a fastener.
Typically (and definitely with regard to self-drilling, self-tapping fasteners), when an operator uses a drive tool, such as a drill, to drive a fastener into a work piece, the operator must use his upper-body strength to apply an axial force to the drive tool. It is advantageous to reduce the amount of upper-body strength an operator must apply to a drive tool to effect the installation of a fastener because doing so reduces the fatigue and physical stress experienced by the operator. This is especially true because oftentimes a large number of fasteners must be installed to complete a job.
Some drive tools are configured such that, if an operator wishes to use the drive tool to install a fastener into a floor, the operator must get on the floor, on his or her knees, in order to use the drive tool to drive the fastener into the floor. Of course, getting on one""s knees every time one installs a fastener in a floor can be uncomfortable and tedious. This is especially true in the case where a large number of fasteners must be installed over a large floor surface area.
Other drive tools, such as those which are disclosed in U.S. Pat. Nos. 3,960,191; 4,236,555; and 5,897,045 are configured such that an operator can remain standing while using the drive tool to install fasteners into a floor. Such drive tools are essentially extended tools connected to a power drill or to some other driving source. Typically, the drive tool is configured such that fasteners are automatically fed to the end of the drive tool. This provides that the operator can use the drive tool to install a plurality of fasteners without having to bend over each time to place a fastener at the end of the tool. Unfortunately, such drive tools are typically relatively heavy and the operator must apply substantial upper-body effort to apply the necessary axial force to the drive tool to install a fastener. Therefore, using such a drive tool, especially if an operator must use the drive tool everyday for extended periods of time, can be tiring.
Accordingly, it is an object of an embodiment of the present invention to provide a drive tool which does not require any upper-body force from an operator to install a fastener.
Another object of an embodiment of the present invention is to provide a drive tool configured such that an operator can easily use his or her own body weight to apply an axial load during a drilling operation.
Briefly, and in accordance with one or more of the foregoing objects, an embodiment of the present invention provides a drive tool having a top portion which is engageable with a drive source, such as a drill, and a lower portion which is engageable with a fastener. The drive tool includes springs which are configured to urge the lower portion and upper portion of the tool away from each other (i.e. relative movement) and provide that a generally axial force is applied to the fastener engaged with the lower portion of the tool. As a result, the operator does not need to apply any upper-body axial force to the drive tool to install the fastener.
Preferably, the lower portion of the drive tool includes one or more foot pads on which an operator may stand, and the spring(s) become compressed when the operator stands on the foot pad(s). As a result of the spring(s) trying to expand under compression, a generally axial force is applied to the fastener engaged with the lower portion of the tool, thereby reducing the amount of upper-body axial force an operator must apply to the drive tool to install the fastener. Hence, the operator can use his or her own body weight to apply an axial load during a drilling operation, and need not use any upper-body force.